Electromagnetic based instruments can be used for measuring properties of matter and/or used for identifying its composition. For example, an electromagnetic based instrument capable of performing magnetic resonance spectroscopy can be used to obtain physical, chemical and/or structural information about matter (e.g., a molecule). Typically, in order to perform magnetic resonance spectroscopy, for example to provide high quality measurements of an object/subject (e.g., high resolution image and/or image contrast), it can be desirable for the magnetic field inside of a zone of measurement (e.g., an area where an object is to be measured is positioned) to be substantially stable and/or uniform. Other applications (e.g., magnetic resonance imaging (MRI)) can also require a high, stable, and/or uniform magnetic field strength.
Some systems that use magnetic fields for measurements can include magnetic coils to create the magnetic fields, with application of current to the coil, while other systems can utilize permanent magnets to create the magnetic fields, which typically do not require application of a current.
One difficulty in creating a magnetic field in a zone of measurement with permanent magnet(s) that is sufficient for magnetic resonance spectroscopy and/or magnetic imaging (e.g., that is substantially stable and/or uniform) is that magnetic fields produced by the permanent magnets(s) can be non-homogeneous, thus typically resulting in a non-homogenous magnetic field within the zone of measurement.
Some current solutions for creating a homogenous and/or stable magnetic field within a zone of measurement using a permanent magnet can include adding additional elements to an imaging device (e.g., coils) and/or increasing the size of the permanent magnets. One difficulty with current solutions is that as the number of elements in a magnetic measurement device increases and/or the size of the permanent magnets increases, the weight, size and/or cost of the device can increase.
Another difficulty with current solutions is that a magnetic measurement device that is heavy can cause a lack of mobility. For example, for magnetic measurement devices in a hospital setting (e.g., magnetic resonance imaging (MRI) devices), a heavy and/or large device can prevent hospital personnel from moving an MRI. This can cause further difficulties, when imaging patients that can be hard to move (e.g., patients that are hooked up to multiple life support and/or monitoring equipment).
In another example, for magnetic measurement devices in an industrial setting (e.g., nuclear magnetic measurement (NMR) devices that measure properties of fluids and/or drilling muds in oil production facilities), a heavy and/or large device can prevent personnel from measuring the fluids/muds at various locations in the processes.
Therefore it can be desirable to achieve a desired magnetic field strength, having sufficient homogeneity and/or stability, and/or reducing a total weight of a magnetic measurement system.